The present disclosure relates to an image forming apparatus that forms an image on a sheet.
Conventionally, in an image forming apparatus that forms an image on a sheet, an image forming portion including a photosensitive drum, an exposure device, a developing device, a transfer device, and a fixing device is disposed. An electrostatic latent image is formed on the photosensitive drum by the exposure device, and the electrostatic latent image is made visible as a toner image by the developing device. Then, the toner image on the photosensitive drum is transferred onto a sheet by the transfer device. The sheet onto which the toner image has been transferred is subjected to a fixing process by the fixing device, and then discharged.
In an image forming apparatus as described above, a sheet cassette is disposed in which a plurality of sheets are stacked and that is detachable from the body of the image forming apparatus. A sheet having a length greater than the depth of the apparatus body is accommodated in such a sheet cassette, and thus techniques enabling the sheet cassette to be extendable are known. The sheet cassette in the extended state is inserted into the apparatus body from a wall portion on one side of the apparatus body, and then attached to the apparatus body in a protruding manner from a wall portion of the apparatus body on the other side to the outside of the apparatus body. At this time, if the top face portion of the sheet cassette protruding to the outside of the apparatus body is exposed to the outside, a foreign object such as a clip may fall on and enter into the apparatus body. For example, a sheet cassette including a lid member that is extendable together with the cassette body is known. Also known is a technique in which a cover member that is extended in the attachment direction of the sheet cassette is extended in advance inside the apparatus body, and the cover member is moved to the outside of the apparatus body simultaneously with the attachment of the sheet cassette.